ATG5 and osteosarcoma: Furthermore, we observed enhanced autophagy flux in TSSC3 overexpressing osteosarcoma cells and demonstrated that TSSC3-induced impairment of tumorigenesis and metastasis in osteosarcoma cells was reduced when autophagy was inhibited using chloroquine (CQ) or under conditions of stable knockdown of ATG5 by lentiviral vectors in vitro and in vivo.